Phenoxyalkanoylamidooxyalkanoic compounds

ABSTRACT

BOTH BROADLEAF WEEDS AND COMMON NOXIOUS GRASSES SUCH AS YELLOW AND GREEN FOXTAIL ARE COMBATED IN FIELDS OF SMALL GRAINS SUCH AS WHEAT, BARLEY AND OATS BY USE OF PHENOXYALKANOYLAMINOOXYLAKANOIC ACIDS AND DERIVATIVES THEREOF, FOR EXAMPLE, 2-PHENOXYPROPANOYLAMINOOXY ACETIC ACID, FORMULATED EITHER AD FREE ACID OR SALTS.

United States Patent U.S. (1260-519 7 Claims ABSTRACT OF THE DISCLOSUREBoth broadleaf weeds and common noxious grasses such as yellow and greenfoxtail are combated in fields of small grains such as wheat, barley andoats by use of phenoxyalkanoylaminooxyalkanoic acids and derivativesthereof, for example, 2 phenoxypropanoylafiinooxy acetic acid,formulated either as free acid or s ts.

DESCRIPTION OF INVENTION This application is a division of US. Ser. No.759,761, filed Sept. 13, 1968 now US. Pat. 3,543,305, which is acontinuation-in-part of US. Ser. No. 668,180, filed Sept. 15, 1967, nowUS. Pat. 3,520,674, which is a continuation-impart of US. Ser. No.374,813, filed June 12, 1964, now US. Pat. 3,457,063.

The chlorophenoxyacetic acid type of herbicides is well known. Thesecompounds are easily formulated and have provedto be effective incombating broadleaf weeds in grain crops but are generally deficientwith respect to activity against the common noxious grasses. When usedin sntficient quantities to be eflective against the grasses, theyseverely injure or kill grain crops. I have discovered a new class ofherbicidal compounds derived from the phenoxyacetic acids which areeasily formulated as amine salts or lower alkyl esters, are highlyactive and at the same time are able to control both broadleaf weeds andsome of the more common noxious grasses in small grains. Briefly, mymethod of combating undesired plant growth comprises applying to thelocus of the plant a herbicidally effective quantity of aphenoxyalkanoylaminooxyalkanoic compound represented by the structuralformula 3! R OH NO o-intlca l -ii-it-0-zia-ii-0 -n" 2 n Both the freeacids and lower alkyl esters are conveniently made by reacting ahaloalkanoic acid or ester 3,660,475 v Patented May 2, 1972 Ice with aphenoxyalkanohydroxamic acid. Preparation of a hydroxamic acid, as wellas both acid and ester herbicides are illustrated by the followingspecific procedures:

(A) Preparation of 2-(4-chloro-2'-methylphenoxy)- acetohydroxamic acidInto a 3 liter, 3 necked round-bottomed flask was placed 49.0 g. (0.7mole) of hydroxylamine hydrochloride, 1500 ml. of toluene and 74.2 g.(0.7 mole) of sodium carbonate. The contents were stirred and the flaskwas cooled in an ice bath to 10 C. To the flask there was then addeddropwise, with stirring, 105 ml. of water during a period of 30 minutes,maintaining the temperature below 10 C. There was then added dropwise,with stirring, 153.0 g. (0.7 mole) of 4-chloro-2-methylphenoxyacetylchloride in 400 ml. of toluene during a period of about 30 minutes. Theice bath was then removed and stirring was continued for an hour. A warmwater bath (45 C.) was then put under the flask and stirring wascontinued for an hour and 45 minutes. The crystalline product wasrecovered by filtration, was washed on the filter with water, then withhexane, was died and recrystallized from a mixture of ethyl acetate andhexane. Weight after recrystallization and drying was 128.8 g., M.P.128-9 C.

Calculated for C H ClNO (percent): C, 50.13; H, 4.67; Cl, 16.44; N,6.48. Found (percent): C, 49.71; H, 4.79; Cl, 16.65; N, 6.81.

(B) Preparation of ethyl 2,4-dichlorophenoxyacetamidooxyacetate Asolution of ethyl bromoacetate (8.35 g., 0.05 mole) in ethanol (50 ml.)was added to a solution of 2-(2',4'- dichlorophenoxy) acetohydroxamicacid (11.8 g., 0.05 mole) in 0.5 N sodium hydroxide (100 ml., 0.05mole). The mixture was stirred, heated and refluxed for 4 hours. Aftercooling to 25 0., water (400 ml.) was added to precipitate the crudeproduct which was removed by filtration and dried. Recrystallizationfrom a mixture of benzene and hexane gave 7.0 g. (43.4%) of product,M.P. -87 C.

Calcd for C H Cl NO (percent): C, 44.74; H, 4.06; N, 4.35. Found(percent): C, 44.31; H, 4.04; N, 4.25.

(C) Preparation of 2,4-dichlorophenoxyacetamidooxyacetic acid A solutionof bromoacetic acid (13.9 g., 0.1 mole) in ice water (50 ml.) wasneutralized with 10% sodium hydroxide (phenophthalein indicator). Thisneutralized solution was added to a solution of 2-(2,-dichlorophenoxy)acetohydroxamic acid (23.6 g., 0.1 mole) in 0.5 Nsodium hydroxide (200 ml., 0.1 mole). The mixture was stirred, heated,and refluxed 4 hours, then cooled to 15 C. and acidified with dilutehydrochloric acid. The crude product was removed by filtration, washedwith water, and dried. Recrystallization from a mixture of ethyl acetateand hexane gave 16.7 g. (56.8%; M.P. 168-70 C.) of product.

Calcd for C H Cl NO (percent): C, 40.84; H, 3.08; N, 4.76. Found(percent): C, 40.40; H, 3.15; N, 4.40.

The compounds listed in table were prepared according to the generalprocedure exemplified above.

Substltuents in generic structural formula X Y Z 'n R R R Empiricalformula M.P., G.

4-01 2-0H3 H H H H 011H1201NO 184-150 3-0151; 3-0H H 0 H H H 012HN0s163-164 2-01 4-01 H 2 H H H 012H1s012NO5 103-105 H H H 0 CH H H CnHisNOs113-115 2-01 4-01 5-01 0 H H H CWH CIsN Os 162-164 3-01 4-01 H 0 H OH; H011H11012NOs 141-143 3-01 4-01 H 0 H H H CIOHQClZNOfi 173-175 2-01 4-015-01 2 H H H CrzHrzClaNOs 124-126 2-01 4-01 H 0 H OH; H 01 H1 012NOs141-142 2-01 4-01 H 0 H H H 012H13C12NO5 168-170 2-01 4-01 H 0 H H 021150l2H13012N0s 85-70 H O H H 02H5 C12H15N 05 77-79 4-01 2-0H3 H 0 H H 02H50 H1s01NO5 53-55 2-01 4-01 5-01 0 H H 02H5 012H 1013NO5 80-82 2-01 4-015-01 2 H H 02Ha CuHmClaNOs 87-89 Combating undesired plant growth So asto have a valid basis for comparison of results, all of the weed controltests discussed below were made on plants of approximately the same age(about two to three weeks) were similarly formulated in water as adiluent, with the aid of suitable emulsifiers and dispersing agents andwere sprayed at a spray volume of about 40 gallons per acre.

2,4-dichlorophenoxyacetic acid was applied post-emergently at a rate of0.75 lb. per acre. Complete control was obtained on the following weeds:wild buckwheat, lambsquarters, corn cockle, pigweed, wild mustard andmorning glory. There was no injury to wheat, barley or oats. There wasno injury to yellow foxtail and only moderate injury to green foxtail.Injury to these weeds, however, was more than compensated by control ofcompeting species, so that the overall results was a complete lack ofcontrol of these two species. When the application rate was reduced to0.5 lb. per acre there was only moderate injury to corn cockle andcomplete lack of control of three species.

2-methyl-4-cblorophenoxyacetic acid was applied postemergently at a rateof 0.75 lb. per acre. Complete control' was obtained on the followingweeds: Wild buckwheat, lambsquarters, corn cockle, pigweed, wildmustard, and morning glory. There was slightly injury to green foxtailwhich was only temporary and no injury to yellow foxtail. There was noinjury to wheat, barley or oats. When the application rate was reducedto 0.5 lb. per acre there was only moderate injury to corn cockle withresulting failure to control three species.

The novel herbicides of this invention are all of higher molecularweight than the phenoxyacetic acid herbicides, so that on a molar basis,one pound per acre application rate of one of the new compounds isroughly comparable to the application of one of the phenoxyacetic acidsat 0.75 lb. per acre. There is substantial variation both in molecularweight and herbicidal activity of the new compounds, with resultingvariation in optimum application rates. The optimum rate under specificclimatic conditions is readily determined by empirical methods withwhich those skilled in the art are familiar. Use of the new herbicidesin the method of this invention is illustrated in the following specificexamples.

EXAMPLE 1 2,4 dichlorophenoxyacetamidooxyacetic acid was applied postemergently to seven species of weeds, barley and oats at the rate of 2lbs. per acre. Injury to barley and oats was slight and only temporary.Complete control was obtained on the following weeds: wild mustard, wildbuckwheat, lambsquarters, yellow foxtail, green foxtail and morningglory. About 75 percent control was obtained on corn cockle.Upon-pre-emergent application at a rate of 10 lb. per acre, completecontrol of crabgrass was obtained with the herbicide, along with severalbroadleaf species.

EXAMPLE 2 4-(2,4-dichlorophenoxy) butyrylaminooxyacetic acid was appliedpre-emergently at 10 lbs. per acre, giving complete control of crabgrasswith only slight, temporary injury to oats. Post-emergent"applicationa't-2 lbs. per acre gave complete control of the following-weeds: rape,flax, green foxtail, giant foxtail,'pigweed, wild buckwheat,lambsquarters, morning glory, and mustard. About 50 to percent controlwas obtained on corn cockle'and yellow foxtail. Injury to barley, coats,and wheat was only slight. 1'

EXAMPLE 3 Q-methyl-4-chlorophenoxyacetamidooxyacetic acid was appliedpost-emergently at2 lbs. per acre. Complete control was obtained on thefollowing weeds: mustard," wild buckwheat, lambsquarters, corn cockle,green 'foxtail, morning glory, pigweed, flax and rape. Approximately 75percent control was obtained on yellow foxtail-and giant foxtail. Injuryto barley and coats was temporary and only slight. At an applicationrate of 10 lbs. per acre, there was obtained complete pre-emergentcontrol of crabgrass and millet, as well asa number of broadleafspecies.

EXAMPLE 4 The ethyl ester of 2,4-dich1orophenoxyacetamidooxyacetic acidwas applied post-emergently at'the rate of lbs. per acre. Completecontrol was obtained on' the following weeds: green foxtail, pigweed,wild buckwheat, lambsquarter and morning glory. Approximately 75 percentcontrol was obtained on corn coclsle. jury to wheat and barley wasslight, and onlytemporaryJ When the same herbicide was mixedintoisoil'at the rate of 10 lbs. per acre, pre-emergent control"wasfbbtained on the following weeds: drabgi'assf coxcomb; brome grass,millet and Hair. There was significant injury} to germinating corn butresults indicated'that'by reduction of application rate, pre-eme'rgentcontrol'ofa substantial number of weeds may be obtainedwithtolerab le'injury to corn. T v I This herbicide is particularly suitable for"'contr0l of weeds, both preand post-emergently, in standing grain crops.

EXAMPLE 5 The ethyl ether of 2-methyl-4-chlorophenoxyacetamidooxyaceticacid was applied post-emergently in aqueous dispersion at 2 lbs. peracre giving complete" control of the following weeds: rape, flax, greenfoxtail, pigweed, wild buckwheat,-lambsquarters and mustard.Approximately 75 percent control was-obtained on corn cockle. There wasno significant injury to oats-or wheat.

When the same herbicide was incorporated in soil at the rate of 10 lbs.per acre, complete pre-emerg'ent'c'ontrol was obtained on crabgrass,coxc'omb,.millet andlflax.

This herbicide is particularly suited to use in standing grain crops tocontrol weeds, both" preand postemergently.

' EXAMPLE-6 2-phenoxypropionamidooxyacetic acidf was appliedpost-emergently in aqueous dispersion-at 2'v lbs. per acre, givingcomplete control of rape, flax, green foxtail, corn cookie, giantfoxtail, pigweed, wild buckwheat, lambsquarters and mustard. There wasno significant injury to oats and wheat.

When incorporated in soil at the rate of 10 lbs. per acre, completecontrol was obtained on crabgrass, coxcomb and flax.

This herbicide is particularly useful for controlling weeds in standingcrops of grains.

EXAMPLE 7 EXAMPLE 8 At post-emergent application rates of both 1 lb. and2 lbs. per acre, the ethyl ester of2,4,5-trichlorophenoxyacetamidooxyacetic acid gave complete control ofmustard, wild buckwheat, lambsquarters, green foxtail and morning glorywith no more than slight injury to barle'y, oats and wheat.

This herbicide is useful in combating weeds, in wheat, particularly inareas where green foxtail presents a serious weed-control problem.

EXAMPLE 9 At a post-emergent application rate of 2 lbs. per acre,3,4-dichlorophenoxyacetamidooxyacetic acid gave complete control ofmustard, wild buckwheat, lambsquarters, green foxtail and morning glory.There was no injury to oats or wheat and only slight injury to barley.

This herbicide is highly selective and may be used at application ratesas high as 5 or 6 lbs. per acre, if desired, to combat thickinfestations of weeds in oats and wheat.

6 EXAMPLE 10 As a post-emergent application rate of 2 lbs. per acre,2,4,5 trichlorophenoxyacetamidooxyacetic acid gave complete control ofmustard, wild buckwheat, lambsquarters, green foxtail and morning glory,with only slight injury to oats. Approximately percent control wasobtained on corn cockle and yellow foxtail. At an application rate aslow as /2 lb. per acre, complete control of wild buckwheat,lambsquarters, green foxtail and morning glory was obtained, with noinjury to barley, oats and wheat.

This herbicide is particularly useful in areas in which green foxtail isa problem in small grains.

I claim:

1. 2,4-dichlorophenoxyacetamidooxyacetic acid.

2. 4 (2',4 dichlorophenoxy)butyrlaminooxyacetic acid.

3. 2 methyl 4 chlorophenoxyacetamidooxyacetic acid.

4. 2-phenoxypropionamidooxyacetic acid.

5. 2 (3',4 dichlorophenoxyacetamidooxy)propionic acid.

6. 3,4-dichlorophenoxyacetamidooxyacetic acid.

7. 2,4,5-trichlorophenoxyacetamidooxyacetic acid.

References Cited UNITED STATES PATENTS 3,449,113 6/ 1969 Neighbors260-519 3,282,987 11/1966 Ellis 260-471 3,457,063 7/1969 Neighbors 260-519 LORRAINE A. WEINBERGER, Primary Examiner R. S. WEISSBERG, AssistantExaminer U.S. Cl. X.R.

fgggy UNITED STATES PATENT OFFICE CERTIFICATE OF CORREC-TKQN Patent No.3,660,475 Dated May 1972 Inventor(s) RalQh P. Neighbors It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

T e I '1 Column 2, line 23, the word "died" should read -dried-. Column4', line 24, the word "coats" should read -oats-. Column 3, in theformula, the Column of figures beginning "184-150" should read-l48l50--.

Column 4, Example 5, line 58, the word "ether" should read -ester--.Column 6, Example 10, line 3, the

word "As" should read -At.

Signed and sealed this 26th day of September 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents

